Side-blast converter furnace



Feb. 16 1926. 1,572,892

T. LEVOZ SIDE BLAST CONVERTER FURNACE Filed Jlgly 18, 1922 Patented Feb. 16, 192%.

UNITE. STATES TOUSSAINT LEVOZ, OF BEER, BELGIUM.

SIDE-BLAST CONVERTER FURNACE.

Application filed. July 18, 1922. Serial No. 5?5,%09.

To all whom it may concern:

Be it known that I, TOUSSAINT Lnvoz, a subject of Belgium, residing at Heer, Provincc dc Namur, Belgium, have i vented certain new and useful Improvements in Side- Blast Converter Furnaces, of which the following is a specification.

The side blast converter furnaces employed at the present day yield generally metal which is blistered, is not homogeneous and is especially very irregular in its granular structure. These very great drawbacks in the manufacture of cast steels are mainly due to unsuitable devices adopted in the construction of those converters.

The present invention has for its object to avoid those drawbacks by providing an improved side-blast converter having the following characteristic features a. The introduction, into the twyers, of an air blast which has been completely deprived of moisture by having been passed first through a suitable drying filter.

b. The introduction of this dry air blast into the twyers under suitable pressure for the proper conversion of the bath Without super-oxidation of the iron owing to the expansion of this air blast in a blast box of very ample dimensions.

0. The introduction of this dried air blast under suitable pressure into the bath in such a manner as to effect a unform distribution thereof without any boiling up, and so as to produce a gyratory motion of the entire mass of molten metal, avoiding all superoxidation of the iron by reason of the combination of tangentially directed twyers having a slight downward slope, preferably with a hearth in the form of an inverted truncated cone.

(Z.'Tl1e discharge of the cinder is facilitated by the provision, above the truncated conical hearth, of a contracted cylindrical portion overhanging the hearth which also allows of conserving the high temperature given off at the surface of the bath for the purpose of superheating the latter.

6. Finally, the construction of the upper part of the converter in the form of a dome for the purpose of collecting any metal that is splashed or projected during the operation and causing it to fall back into the bath, and also for the purpose of assuring a good distribution of the added reducing agents in the bath at the termination of the 0011- verting operation.

A constructional form of an improved converter according to this invention is illustrated by way of example in the accompany ing drawings, in which Figure l is a vertical section of the improved converter.

Figure 2 is a horizontal section taken along the line XX of Figure 1.

As shown, the improved converter consists of a hearth 1 having the form of an inverted truncated cone surmounted by a contracted cylindrical shaft 2 which opens out into a dome 3 provided with the pouring throat l.

5 is the lining of any suitable material of the converter which in its cylindrical portion is surrounded by a Very large an nular blast box 6 into which the blast entersthrough one of the hollow trunnions 7 that serve for tipping the converter. This blast box is separated vertically into two portions by a partition 8 which compels the blast to pass through a filter constituted by two perforated partitions 9, 9, comprising between them a packing of suitable drying material 10 which is sufficiently heavy or resistant not to be carried over by the blast into the twyers, for instance, pumwe 11 are the twyers which have a slight downward slope and are preferably arranged tangentially to a circle a, the diameter of which is one-third of that of the hearth. 12 is the tapping hole for the discharge of the slag as the latter is formed. 13 is an inspection door for the twyers.

.1 1, 14': are doors through which the pumice or other drying material 10 may be renewed.

The working of the improved converter is as follows The air coming from the blast engine, at a pressure of for instance, 40 to centimetres of mercury, above atmospheric pressure passes through [the filter whence it passes out completely dry, because the temperature existing in the blast box is Sullicient to vaporize any water that may have been contained in the air and to promote its absorption by the pumice. This air, thus dried, expands in the blast box and enters the twyers at a suitable pressure (about 30 cms. of mercury) so as to enable the bath of molten cast iron to be converted without superoxidation of the iron.

The dimensions of the hearth are made such that the bath of molten cast iron which it contains shall be a few centimetres higher than the plane of the twyers when the converter is vertical, and thus the desiliconiz'ation is properly assured.

Owing to the tangential direction of the twyers, the air on entering the hearth imparts a gyratory motion to the upper layer of the bath of molten metal. As this motion is being established, the converter is tilted back into the vertical position, and the slightly downward slope of the twyers causes the air to reach the centre of the bath, thus producing a general whirling of the entire mass of metal. The occurrence of this whirling motion is aided by the fact that the upper cylindrical layer of the bath has a greater thickness than the lower truncated conical layer of the said bath.

The overhanging portion 21 formed by the cylindrical shaft 2 above the hearth compels the air blown in through the twyers to enter the bath instead of escaping by creeping along the inside walls of the converter.

The small quantity of iron oxide formed under these conditions will act as an cacious refining agency, not by virtue of the difference between the densities of the refined metal and of the metal still to he refined, but by the mechanical action of the jets of air which promotes dccarburation.

The contracted form of the cylindrical shaft 2 has the effect on the one hand of conserving the high temperature disengaged at the surface of the bath, and on the other hand of giving a larger thickness to the layer of slag in such a manner as to facilitate its discharge through the outlet 12 as it is formed. This gradual discharge thus prevents any silicon from re-entering the bath due to a decarburation in the presence of the slag.

The decarburation thus takes place without unduly violent boiling up, and it pro duces very compact slag which swells up very readily so that it can be discharged through the outlet 12 without carrying any liquid iron with it.

The small quantity of splashed metal is collected in the dome 3 whence it falls back into the bath. This dome-shape of the upper part of the converter allows also of gathering the converted bath into a compact mass and thus enables the added reducing agents to be thoroughly distributed in the bath.

By reason of the decarburation taking place without excessive boiling up, the flame generated by the steady combustion of the carbon passes in an absolutely steady manner out through the throat l of the converter with a minimum outrush of flame, thus allowing the termination of the operation to be ascertained with much more accuracy than with any other converters.

The wear and tear of the refractory lining 5 being very small owing to the improved design and working of the improved converter, and since the improved shape of the hearth gives a smaller wearing surface, the result will be a very slight increase in the internal volume of the said hearth as a result of successive, converting operations, and it will therefore not be necessary to increase the charges for following workings.

The conditions of the converting operations will thus remain practically constant, which is an advantage that has not yet been realized in the known side-blast converters.

Having now particularly described and ascertained the nature of my said invention and in what manner the same is to be performed, I, declare that what I claim is:-

A side-blast converter comprising a drying filter arranged for instance in the blast box, through which the blast is caused to pass on its way to the twyers for the purpose of being freed from the whole of its contained moisture.

Signed at Brussels, in the Kingdom of lelgium, this th day of June, 1922.

'IlOUSSAINT LEVOZ. 

